title: Humoral and cellular immunity in chromium picolinate-supplemented lambs.
abstract: The effects of oral supplementation of chromium picolinate (CrPic) on humoral and cellular immunity in sheep were investigated. Twenty-four male lambs divided into four treatments and received different dosages of CrPic: placebo (0), 0.250, 0.375, and 0.500 mg of chromium/animal/day during 84 days. The base ration was Panicum maximum cv Massai hay and concentrate. Blood samples were collected fortnightly for total and differential leukocyte counts. On days 28 and 56, the lambs were challenged with chicken ovalbumin I.M. Serum samples were collected on days 46 and 74 and subjected to an indirect enzyme-linked immunosorbent assay to measure IgG anti-ovalbumin. The cell-mediated immune response was determined by a delay-type hypersensitivity test using phytohemagglutinin. CrPic did not significantly affect humoral immunity in lambs but there was a negative effect on cellular immunity (P < 0.05) as Cr supplementation increased. Therefore, the level of Cr supplementation for lambs must be better studied to address its effect on stressed animals or the possible toxic effects of Cr on the animal itself or its immune system.
authors.affiliation: Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Brasília, Distrito Federal 70910-900, Brazil. dallago@unb.br
authors.forename: B  S L
authors.initials: B
authors.lastname: Dallago
authors.forename: C  M
authors.initials: C
authors.lastname: McManus
authors.forename: D F
authors.initials: DF
authors.lastname: Caldeira
authors.forename: A
authors.initials: A
authors.lastname: Campeche
authors.forename: R T
authors.initials: RT
authors.lastname: Burtet
authors.forename: T  P
authors.initials: T
authors.lastname: Paim
authors.forename: E F
authors.initials: EF
authors.lastname: Gomes
authors.forename: R  P
authors.initials: R
authors.lastname: Branquinho
authors.forename: S  V
authors.initials: S
authors.lastname: Braz
authors.forename: H
authors.initials: H
authors.lastname: Louvandini
mesh_terms: D000818:Animals; D019587:Dietary Supplements; D006968:Hypersensitivity, Delayed / Q000097:blood / Q000276:immunology; D007111:Immunity, Cellular / Q000187:drug effects*; D056724:Immunity, Humoral / Q000187:drug effects*; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007502:Iron Chelating Agents / Q000494:pharmacology*; D008297:Male; D010848:Picolinic Acids / Q000494:pharmacology*; D012756:Sheep
chemical_list: D007074:Immunoglobulin G; D007502:Iron Chelating Agents; D010848:Picolinic Acids; C030614:picolinic acid